CN109061526A

CN109061526A - The detection of single short circuit LED in LED chain

Info

Publication number: CN109061526A
Application number: CN201810588437.XA
Authority: CN
Inventors: M·帕玛托; M·加尔瓦诺; R·古拉; A·佩勒格里尼; D·萨托利; E·托纳佐
Original assignee: Infineon Technologies AG
Current assignee: Infineon Technologies AG
Priority date: 2017-06-09
Filing date: 2018-06-08
Publication date: 2018-12-21
Anticipated expiration: 2038-06-08
Also published as: CN109061526B; US10187955B2; US20180359824A1

Abstract

This disclosure relates to which one kind can detecte the circuit of the single short circuit in load (such as light emitting diode (LED)) chain.The circuit can drive multiple LED chains or single led chain, to determine whether one or more LED in the LED in LED chain is no longer worked due to short circuit.Circuit determines whether LED chain voltage meets threshold value, which is based on single led voltage drop.Therefore, the quantity regardless of the LED in LED chain, can be for using identical circuit.In addition, the quantity of the LED chain regardless of circuit drives, in addition to for output pin can not used according to the circuit of the technology of the disclosure other than electric current is sent to those of LED chain output pin.

Description

The detection of single short circuit LED in LED chain

Technical field

This disclosure relates to the fault detection in electrical load chain.

Background technique

There is the circuit of one or more branch of electrical load chain (such as light emitting diode (LED) chain) for driving Device, it may be necessary to the failure of a load in detection load.Due to open circuit in the example of the load of failure, for having The branch of open circuit, electric current will stop flowing.Circuit device can detecte the electric current stopping for the branch, and therefore detection is opened Road failure.Due to short circuit in the example of the load of failure, the load faulty detected in load bearing chain may have more challenge.

Summary of the invention

Generally, this disclosure relates to which one kind can detecte the single short circuit in load (such as light emitting diode (LED)) chain Circuit.The circuit can drive multiple LED chains perhaps single led chain to determine one in the LED in LED chain or more Whether a LED is no longer worked due to short circuit.Circuit determines whether LED chain voltage meets threshold value, which is based on single led electricity Pressure drop.Therefore, the quantity regardless of the LED in LED chain, can be for using identical circuit.In addition, no matter circuit How is the quantity of the LED chain of driving, other than being used to electric current being sent to those of LED chain output pin, according to the disclosure The circuit of technology can not use output pin.

In one example, this disclosure relates to include the circuit of short-circuit detecting circuit, which includes: single Short-circuit detecting output element；And selector circuit, the selector circuit are configured to from one or more output element Each output element receives series load voltage, and selects a series load from one or more output element Voltage, wherein the short-circuit detecting circuit, which is configured that, compares selected series load voltage with predetermined threshold voltage value Compared with, and meeting predetermined threshold voltage value in response to selected series load voltage, short-circuit detecting circuit is configured to single Output short-circuit detects signal at short-circuit detecting circuit output.

In another example, this disclosure relates to which system, the system include: multiple LED strings, in which: every in multiple LED strings A LED string includes concatenated N number of LED, wherein N is greater than 1 integer, and each LED tool in N number of LED in LED string There is expected forward drop；Drive circuit, the drive circuit include multiple output elements, in which: each corresponding output member Part is coupled to corresponding LED string, and drive circuit is configured to pass from the corresponding output electric current of each corresponding output element It send to each corresponding LED and goes here and there；Selector circuit, the selector circuit are configured to select the series connection in multiple series load voltages negative Carry voltage, wherein the corresponding series load voltage of each of multiple series load voltages is gone here and there to the corresponding LED in multiple LED string It is corresponding；Comparison circuit, which, which is configured that, determines whether selected series load voltage meets predetermined threshold voltage Value, and meet predetermined threshold voltage value in response to the selected series load voltage of determination, output short-circuit detects signal.

In another example, this disclosure relates to a kind of method, this method comprises: passing through short-circuit detecting circuit and short to this Each of one or more output element of alignment detection circuit output element, transmission, which is gone to, is coupled to each output element Each series load output electric current, in which: each series load includes N number of load, and N is greater than 1 integer；Pass through Short-circuit detecting circuit determines the corresponding string in one or more series load for being coupled to one or more output element Join the corresponding series load voltage of load；Selected by being selected from one or more series load voltage by short-circuit detecting circuit The series load voltage selected；Determine whether selected output voltage meets predetermined threshold voltage value by short-circuit detecting circuit； And meet threshold voltage value in response to the selected output voltage of determination, it is detected and is believed by short-circuit detecting circuit output short-circuit Number.

One or more exemplary details of the disclosure is elaborated in following attached drawing and explanation.The disclosure it is other Feature, objects and advantages will be apparent by description and accompanying drawings and claims.

Detailed description of the invention

Figure 1A is illustrated according to one or more kinds of technologies of the disclosure for detecting a series of short circuit in loads The schematic block diagram of the example high-side driver multi-channel circuit of load.

Figure 1B is depicted according to one or more kinds of technologies of the disclosure with the short of high side connection drive circuit The conceptual timing diagram of the operation of alignment detection circuit.

Fig. 2A is the schematic frame for illustrating the example low side driver multi-channel circuit of multiple series loads of driving LED Figure.

Fig. 2 B is depicted according to one or more kinds of technologies of the disclosure with the short of downside connection drive circuit The conceptual timing diagram of the operation of alignment detection circuit.

Fig. 3 A is to illustrate to can be used for detecting in a series of loads according to one or more kinds of technologies of the disclosure The schematic block diagram of short circuit load, the single series load of driving example multichannel high-side driver circuit.

Fig. 3 B is to depict to drive the more of single led series load according to the having for one or more kinds of technologies of the disclosure Channel high side connects the conceptual timing diagram of the operation of the short-circuit detecting circuit of drive circuit.

Fig. 4 A is the schematic diagram for illustrating the example low side driver multi-channel circuit of single series load of driving LED.

Fig. 4 B is depicted according to one or more kinds of technologies of the disclosure for powering to a LED series load Multichannel downside connects the conceptual timing diagram of the operation of the short-circuit detecting circuit of drive circuit.

Fig. 5 is shown according to the concept of the example embodiment of the short-circuit detecting circuit of one or more kinds of technologies of the disclosure Meaning property block diagram.

Fig. 6 is in a load in a series of loads of detection illustrated according to one or more kinds of technologies of the disclosure Short circuit circuit device operation example modes flow chart.

Specific embodiment

This disclosure relates to which one kind can detecte the electricity of the single short circuit in load bearing chain (such as light emitting diode (LED) chain) Road.Circuit can drive multiple LED chains or single led chain, be with one or more LED determined in the LED in LED chain It is no no longer to be worked due to short circuit.Circuit determines whether LED chain voltage meets threshold value based on single led voltage drop.Cause This, the quantity regardless of the LED in LED chain can use identical circuit.

Maximum and/or minimum voltage of the technology of the disclosure based on LED chain are compared between threshold voltage.It can be in electricity Threshold voltage is generated inside road (such as in integrated circuit (IC)), or can provide threshold voltage in circuit external.This public affairs One advantage of the technology opened is: in addition to for may be not present additional other than electric current is sent to those of LED chain output pin Or dedicated output pin.The other examples of short-circuit detecting circuit may need additional and dedicated pin.In some instances, often A LED chain needs dedicated short-circuit detecting pin.In other words, driving some short-circuit detecting circuits of five LED chains may need At least five additional short-circuit detecting output pins.Other examples LED short-circuit detecting circuit may include digital communication bus and Whether Digital Logic and register are broken down with the LED in the multiple LED chains of determination.In contrast, in addition to for passing electric current It send to except those of LED chain output pin, it can be without using additional or dedicated output according to the circuit of the technology of the disclosure Pin.The advantages of being provided according to the circuit of the disclosure better than other detection circuits, advantage includes less pin, smaller Size and reduced complexity.

The technology of the disclosure can be applied to both single channel LED driver and multi-channel LED driver.According to the disclosure The circuit of technology the flexibility using multi-path driver can be provided, some of or whole channels are electrically short-circuited to each other, and Do not lose the ability for detecting single led short circuit.For example, in some applications, user can make the logical of multi-path driver circuit One or more channel in road is shorted together, to increase the electric current flowed through in single led chain.According to the more of the disclosure Channel circuit (wherein, whole channels are shorted together to drive single led chain) still can detecte single in single led chain Short-circuit LED.The advantages of being provided according to the circuit of the disclosure better than other types of short-circuit detecting circuit, including providing can be with A kind of IC model used in multichannel application or single channel application.A kind of ability that model meets many applications can mention For following advantages: such as reduction inventory reduces manufacturing cost, simplifies product selection and similar advantage.

Figure 1A is illustrated according to one or more kinds of technologies of the disclosure for detecting a series of short circuit in loads The schematic block diagram of the example high-side driver multi-channel circuit of load.Circuit 10 may include current source 14 to 18, to be used for To circuit one or more output element (34A to each of 34C) output element transmission go to be coupled to it is each defeated Series load (output electric current (the Iout1 to Iout3) of 32A to 32C) of element out.Including circuit 10A and current source 14 to 18 The circuit 10 of the two can be considered short-circuit detecting circuit.In other examples, circuit 10A can be considered short-circuit detecting circuit And it is separated with current source circuit, but is connected to current source output 34A to 34C via terminal 36A to 36C.In other words, short circuit inspection Slowdown monitoring circuit can only include the circuit element of such as selector circuit as shown in circuit 10A and comparison circuit etc.At it In its example, short-circuit detecting circuit can also include the driver element or other types of of such as current source 14 to 18 etc Driver element.In the disclosure, term current driver can be used for referring to current source.In other words, in some instances, short Alignment detection circuit may include the source (such as current source) for powering to series load.In other examples, short-circuit detecting electricity Road can not have the source to power to series load, but be coupled to the output in source to determine the series load electricity at output Pressure.

Current source 14 to 18 may include any kind of current source that can supply electric current, such as current regulator.Such as Described in the example of Figure 1A, current source 14 to 18 receives power from Vbat12, however, Vbat can indicate any power supply (such as regulated power supply) and it is not necessarily limited to battery.Each current source includes output element (34A to 34C).Current source 14 to 18 Electric current will be exported, and (Iout1 to Iout3), which is supplied to, to be coupled to each series load of each output element 34A to 34C (32A is extremely Anode-side 32C).The cathode side of each series load 32A to 32C is coupled to ground.

Figure 1A and Fig. 2A depicts three series loads, however, the other examples of circuit 10 and 40 may include be more than or Person is less than three series loads.Through the disclosure, series load can also be known as to branch load, LED chain.In other words, it goes here and there Connection load 32A to 32C can be considered the branch load 32A to 32C for the multiple loads powered by circuit 10 or 40.Description electricity The another way on road 10 or 40 can be the multi-channel circuit powered to three channels.It can be (all as follows by other examples Fig. 3 A and Fig. 4 A in face) it is described as the multi-channel circuit powered to single channel or single series load.

Current source 14 is connected to the series load 32A including LED 25.For simplification figure and explanation, the disclosure will be focused on Each load of series load as LED.In other examples, the load that can be other types, such as light bulb, electricity are loaded Source and similar load.Other LED to series load 32A into 32C are not numbered.The example of Figure 1A is negative by each series connection Load is portrayed as including three LED, but in other examples, and series load may include any amount of LED.

Circuit 10A can be considered the short detection unit of circuit 10.Term short-circuit detecting circuit and short detection unit It can be used interchangeably in the disclosure.Circuit 10A includes selector circuit (minimum value selector 20), comparison circuit (comparator 22), threshold voltage vt hresh24 and output Vflag 28.Circuit 10A can be coupled to each series connection via terminal 36A to 36C 32A to 32C is loaded, and receives load voltage Vout1 to Vout3.Respectively, terminal 36A is connected to the sun of series load 32A Pole side and load voltage Vout1 is received, terminal 36B is connected to the anode-side of series load 32B and receives load voltage Vout2, terminal 36C are connected to the anode-side of series load 32C and receive load voltage Vout3.Unmarked end in figure 1A Sub- 36B is with simplified diagram.

The drive circuit for being connected to the anode-side of the series load of LED can be considered high-side driver circuit.Pass through Fig. 3 A describes similar example high-side driver circuit.The drive circuit for being connected to the cathode side of the series load of LED can To be considered low driver circuit.The example of low driver circuit can be found in Fig. 2A and Fig. 4 A.

Load voltage Vout1 to Vout3 depends on series load, rather than the output of current source 14 to 18.For example, series connection Loading 32A includes three LED, and each LED has LED voltage drop V_LEDi.Then, according to following equation, series load voltage is LED voltage drop V_LEDiSummation:

In the roughly the same example of all LED voltage drops in wherein series load 32A, the series connection of series load 32A Load voltage Vout1 is Vout1=N x V_LED=3 x V_LED, wherein N is the load number indicated in series load 32A Integer.

The selector circuit of circuit 10A may include minimum value selector 20.Various technologies can be used to implement minimum Value selector circuit (such as minimum value selector 20), including can be by discrete parts, integrated circuit (IC) or similar techniques structure Logic circuit, microprocessor circuit and the other types of circuit built.Minimum value selector 20 receives multiple input voltages, and Select the voltage with minimum voltage value.For example, each LED in series load 32A to 32C is V_LEDIn the case where, each string Joining load voltage will be roughly equal.In other words:

V_out1=V_out2=V_out3=N × V_LED=3 × V_LED

And the output Vselect 38 of minimum value selector 20 can be with substantially 3V_LED.However, wherein LED 25 by In short circuit and in the example of failure, then Vout1=2xV_LED, and minimum value selector 20 will select minimum voltage.Therefore, V_SELECT=Vout1=2V_LED.In some instances, selector circuit (such as minimum value selector 20) may include for dropping The divider of the common-mode voltage of the input of low comparator 22/voltage scaling device (scaler).It can be by voltage scaling device application In each output, (36A to 36C) directly applies to V_SELECT38 voltages.The solution is used on the concept map of following Fig. 5 The example of scheme.

Circuit 10A includes comparison circuit, and in the example of Figure 1A, comparison circuit is comparator 22.In other examples, electric Road 10A may include other types of comparison circuit.Comparator 22 receives Vselect 38 in anti-phase input, and will Vselect 38 and predetermined threshold voltage V_THRESH24 are compared.In response to selected series load voltage Vselect 38 Meet predetermined threshold voltage value V_THRESH24, short-circuit detecting circuit (circuit 10A) is configurable to defeated at short-circuit detecting output Short-circuit detection signal out, in the example of Figure 1A, short-circuit detecting output is the output Vflag 28 of comparator 22.

Other numbers or analog circuit 26 can receive short-circuit detection signal Vflag 28 from the output of circuit 10A, and And other functions are executed using Vflag.In some instances, other functions may include: to send alert message or starting Warning indicator (such as indicator light), the warning indicator is by there may be short circuits to lead in a LED in the LED of series LED Know to user.

Figure 1B is depicted according to one or more kinds of technologies of the disclosure with the short of high side connection drive circuit The conceptual timing diagram of the operation of alignment detection circuit.The timing chart sketches of Figure 1B Figure 1A's has showing for short trouble in LED 25 Operation in example.

The timing diagram of Figure 1B include the curve graph of Vout1, the build-up curve figure of Vout2 and Vout3, Vselect 38 song The curve graph of line chart and Vflag 28.LED 25 forms short circuit into t1 in period t0, it means that V_LED25Period t0 extremely It is essentially a zero during t1.Vout1 is the series load voltage of series load 32A, and in the example of Figure 1B, all LED electricity The substantially identical value V of pressure drop_LED.Therefore, in period t0 to during t1, Vout1 will be from about 3V_LEDChange into about 2V_LED。 Other series load voltage Vout2 and Vout3 are in period t0 to generally remaining constant during t1.

It is configured to receive series load electricity from each of one or more output element output element 34A to 34C The selector circuit for pressing Vout1 to Vout3 is minimum value selector 20.Minimum value selector 20 is configurable to selection from one The minimum series load voltage of a or multiple output elements.At time t0, minimum value selector 20 selects Vout1, and Vout1 is exported as Vselect 38.Therefore, as shown in the example of Figure 1B, at substantially t0, Vselect also will be about 2x V_LED。

In this example, Vthresh 24 can be selected as V smaller than the expection series load of global function series load_LED's Certain a part.In the example of Figure 1A and Figure 1B, Vthresh 24 is portrayed as about:

3×V_LED-0.5×V_LED=(N-0.5) × V_LED·.

In other examples, V_LEDPart can be with 1/2V_LEDDifference, such as 3/4V_LED、1/4V_LEDOr V_LEDIt is a certain Other parts ensure that short-circuit detecting circuit will test the single short circuit load in series load, while avoiding false inspection Survey instruction.

In some instances, series load may include the LED with different voltage drops.Vthresh 24 can be set It is set to a part of minimum LED voltage drop.For example, series load 32A may include three LED, the voltage drop point of these three LED It Wei not 0.8V, 0.7V and 0.6V.It is expected that series load can be V_LEDiSummation=0.8V+0.7V+0.6V=2.1V. Vthresh 24 can be set to a part of the small 0.6V voltage drop of series load than expected, such as 2.1V -1/2x 0.6V= 1.8V.In this example, short-circuit detecting circuit will be configured to detection three LED in any LED whether due to short circuit failure.

As described above, short-circuit detecting circuit 10A be configurable to by selected series load voltage Vselect 38 with Predetermined threshold voltage value Vthresh 24 is compared.Meet in response to selected series load voltage Vselect 38 predetermined Threshold voltage value Vthresh 24, short-circuit detecting circuit 10A are configurable to export at single short-circuit detecting circuit output short Detect signal Vflag 28 in road.In the example of Figure 1A (high-side driver circuit), when Vselect 38 is less than Vthresh 24 When (Vselect < Vthresh), Vselect 38 meets threshold value Vthresh 24.In some instances, circuit 10A can be configured Are as follows: when Vselect 38 is less than or equal to Vthresh 24 (Vselect≤Vthresh), Vselect 38 meets threshold value.

Substantially at time t0, Vselect 38 meets Vthresh 24, and comparator 22 can be detected with output short-circuit Signal Vflag 28.Substantially at time t1, the short trouble of LED 25 no longer exists, and Vout1 rises back 3x V_LED。 Vselect 38 also increases to 3x V_LED, and no longer meet threshold value Vthresh 24.In response, comparator 22 can when Between stop output short-circuit at t1 and detect signal Vflag 28.

The circuit of the disclosure can provide multiple advantages better than other types of short-circuit detecting circuit.Show as one Example, does not need additional and dedicated pin, such as can need for LED each series load or branch load it is dedicated The additional and dedicated pin found in other short-circuit detecting circuits of pin.In other words, in addition to for electric current to be sent to LED's Except those pins, additional or dedicated pin is not needed.In some instances, the output of comparator 22 needs not be dedicated and draws Foot.The output of comparator 22 can be only the circuit or system (such as number or analog circuit to responsible management LED short circuit 26) connection.As by described in for Fig. 2A and Fig. 2 B, another advantage can be answered according to the circuit of the technology of the disclosure below For both single channel driver and multi-path driver.This provides the multichannel being electrically short-circuited to each other using some or all channels The flexibility of driver detects the ability of single led short circuit without losing.For example, client can make some or all channels It is shorted together, to increase the series load of the magnitude of current or LED in single chain.

Another advantage is not need special digital communication bus according to the circuit of the technology of the disclosure.It does not need from outside system System provides digital information, the quantity of the LED in each series load of such as LED.It avoid the need for that number bus can be dropped The cost and complexity of the application of the circuit of the low usable disclosure.

Fig. 2A is the schematic frame for illustrating the example low side driver multi-channel circuit of multiple series loads of driving LED Figure.Other than current source 14 to 18 is connected to the cathode side of series load 32A to 32C as low side driver, retouched by Fig. 2A The function for the circuit 40 drawn and the circuit 10 of Figure 1A are similar.The identical attached drawing between Figure 1A and Fig. 2A and the other figures of the disclosure Label instruction has the component of identical function and performance.

Similar to the circuit 10 described above in connection with Figure 1A, circuit 40 may include current source 14 to 18, to be used for electricity (34A to each of 34C) output element transmits or puts into (sink) from coupling to one or more output element on road To the series load (output electric current (Iout1 to Iout3) of 32A to 32C) of each output element.Including circuit 40A and electric current The circuit 40 in both sources 14 to 18 can be considered short-circuit detecting circuit.In other examples, circuit 40A can be considered short circuit Detection circuit, and separated with current source circuit, but be connected to current source output 34A to 34C via terminal 36A to 36C.

The function of Vbat 12 with as above in connection with identical described in Figure 1A.Vbat 12 is connected to each series load The anode-side of 32A to 32C.Current source 14 is connected to series load 32A, and series load 32A includes LED 25.Equally, electric current Source 16 is connected to series load 32B, and current source 18 is connected to series load 32C.In the example of the low side driver of Fig. 2A In, current source 14 to 18 puts into ource electric current to ground.

Circuit 40A can be considered the short-circuit detecting circuit of circuit 40.Circuit 40A includes selector circuit (maximum value choosing Select device 30), comparison circuit (comparator 22), threshold voltage vt hresh 24A and output Vflag 28.Circuit 40A can be through Each series load 32A to 32C is coupled to by terminal 36A to 36C, and receives load voltage Vout1 to Vout3.Respectively, Terminal 36A is connected to the cathode side of series load 32A and receives load voltage Vout1, and terminal 36B is connected to series load The cathode side of 32B and load voltage Vout2 is received, terminal 36C is connected to the cathode side of series load 32C and receives load Voltage Vout3.Unmarked terminal 36B is in fig. 2 with simplified diagram.

As described in above with respect to Figure 1A, load voltage Vout1 to Vout3 depends on series load, rather than current source 14 To 18 output.The selector circuit of circuit 40A is maximum-value selector 30.As minimum value selector 20, it can be used Various technologies implement maximum-value selector 30, including what can be constructed by discrete parts, integrated circuit (IC) or similar techniques Logic circuit, microprocessor circuit and other types of circuit.Maximum-value selector 30 receives multiple input voltages, and selects Select the voltage with maximum voltage value.It is V in each LED of series load 32A to 32C_LEDIn the case where, each series load Voltage will be roughly equal.In other words:

V_out1=V_out2=V_out3=V_bat-N×V_LED=V_bat-3×V_LED

And the output Vselect 38A of maximum-value selector 30 can be about Vbat-3V_LED.However, LED wherein 25 due to short circuit and in the example of failure, then Vout1=Vbat-2xV_LED, and maximum-value selector 30 will select highest electricity Pressure.Therefore, V_SELECT=Vout1=Vbat-2V_LED。

Circuit 40A includes comparison circuit (comparator 22).In other examples, circuit 40A may include other types of Comparison circuit.Comparator 22 receives Vselect 38 in non-inverting input, and Vselect 38 and predetermined threshold is electric Press Vbat 12-V_THRESH24A is compared.Meet predetermined threshold in response to selected series load voltage Vselect 38 Voltage value Vbat 12-V_THRESH24A, short-circuit detecting circuit (circuit 40A) are configurable to export at short-circuit detecting output short Signal is detected on road, and in the example of Figure 1A to Fig. 4 A, short-circuit detecting output is the output Vflag 28 of comparator 22.

Fig. 2 B is depicted according to one or more kinds of technologies of the disclosure with the short of downside connection drive circuit The conceptual timing diagram of the operation of alignment detection circuit.It is similar to fig. 1 above B, the timing chart sketches of Fig. 2 B Fig. 2A in LED Operation in 25 examples with short trouble.

The timing diagram of Fig. 2 B includes the curve graph of Vout1, the build-up curve figure of Vout2 and Vout 3, Vbat 12- The curve graph of Vselect 38 and the curve graph of Vflag 28.LED 25 forms short circuit into t1 in period t0, it means that V_LED25 in period t0 to essentially a zero during t1.Vout1 is the series load voltage of series load 32A, and Figure 1B extremely In the example of Fig. 4 B, all LED voltage drops are all roughly the same value V_LED.Therefore, in period t0 to during t1, Vout1 will be from About Vbat-3V_LEDIncrease to about Vbat-2V_LED.Other series load voltage Vout2 and Vout3 are in period t0 to during t1 Generally remain constant.

It is configured to receive series load electricity from each of one or more output element output element 34A to 34C The selector circuit for pressing Vout1 to Vout3 is maximum-value selector 30.Maximum-value selector 30 is configurable to selection from one The maximum series load voltage of a or multiple output elements.At time t0, maximum-value selector 30 selects Vout1, and Vout1 is exported as Vselect 38.Therefore, at substantially t0, Vselect also will be about Vbat-2V_LED。

In this example, Vthresh 24A can be selected as V_LEDSome part.It, will in the example of Fig. 2A and Fig. 2 B The input for going to the non-inverting input of comparator 22 is portrayed as about:

Vbat-Vthresh=Vbat- (3 × V_LED-0.5×V_LED)=Vbat-2.5 × V_LED·In other examples, V_LED Part can be with 1/2V_LEDDifference, such as 3/4V_LED、1/4V_LEDOr V_LEDSome other parts, ensure short-circuit detecting Circuit will test the single short circuit load in series load, while avoid false detection instruction.

As described above, short-circuit detecting circuit 40A be configurable to by selected series load voltage Vselect 38 with Predetermined threshold voltage value Vbat 12-Vthresh 24A is compared.In response to selected series load voltage Vselect 38 meet predetermined threshold voltage value Vbat 12-Vthresh 24A, and short-circuit detecting circuit is configurable in single short-circuit detecting Circuit output output short-circuit detects signal Vflag 28.In the example of Fig. 2A (low driver circuit), work as Vselect 38 be greater than threshold value (12-Vthresh24A of Vselect > Vbat) when, Vselect 38 meets threshold value Vbat 12-Vthresh 24A.In some instances, circuit 40A is configurable to: when Vselect 38 is more than or equal to threshold value Vbat 12- When Vthresh 24A, Vselect38 meets threshold value.

Substantially at time t0, Vselect 38 meets threshold value Vbat 12-Vthresh 24A, and comparator 22 can be with Output short-circuit detects signal Vflag 28.Substantially at time t1, the short trouble of LED25 no longer exists, and Vout1 reduces To Vbat-3V_LED, so that Vselect 38 be made also to be decreased to Vbat-3V_LED.At time t1, Vselect 38 no longer meets threshold Value Vbat 12-Vthresh 24A.In response, comparator 22 can stop output short-circuit detection signal at time t1 Vflag 28。

Fig. 3 A is to illustrate to can be used for detecting in a series of loads according to one or more kinds of technologies of the disclosure The schematic block diagram of short circuit load, the single series load of driving example multichannel high-side driver circuit.Circuit 50 can be with Including current source 14 to 18, for one or more output element (each of the 34A to 34C) being shorted together Output element transmission output electric current, to drive a series load 32A for being coupled to each output element.Including circuit 50A and The circuit 50 of both current sources 14 to 18 can be considered short-circuit detecting circuit.In other examples, circuit 50A can be considered Short-circuit detecting circuit, and separated with current source circuit, but be connected to current source output 34A to 34C via terminal 36A to 36C.

As all Figure 1A to Fig. 4 A, current source 14 to 18 can be any current source that can supply electric current, such as Current regulator.As described in the example of Figure 1A to Fig. 4 A, current source 14 to 18 receives power from Vbat 12, however, Vbat It can indicate any power supply (such as regulated power supply), and be not necessarily limited to battery.Each current source includes that (34A is extremely for output element 34C).Current source 14 to 18 is combined will export electric current ((Iout1+Iout1+Iout3=3x I_OUTi) be supplied to be coupled to it is every The anode-side of the series load 32A of a output element 34A to 34C.The cathode side of series load 32A is coupled to ground.

Fig. 3 A and Fig. 4 A described below can be considered the multichannel powered to single channel or single series load Circuit.The example of Fig. 3 A and Fig. 4 A depict the triple channel driver powered to single series load.In other examples, it is more than It three channels can be to single load supplying.In other examples, current source 14 and 16 can be combined with negative to single series connection Power supply is carried, and current source 18 is also powered to the second series load.Other examples may include any group of channel and series load It closes.

Current source 14 to 18 is connected to the series load 32A including LED 25A.For simplification figure, not to series load 32A In other LED be numbered.Series load 32A is portrayed as including three LED by the example of Fig. 3 A, but in other examples, Series load may include any amount of LED.

Circuit 50A can be considered the short-circuit detecting circuit of circuit 50.Circuit 50A includes selector circuit (minimum value choosing Select device 20), comparison circuit (comparator 22), threshold voltage vt hresh 24 and output Vflag 28.Circuit 50A can be via Terminal 36A to 36C is coupled to series load 32A, and receives load voltage Vout1 to Vout3, in the example of Fig. 3 A, bears Carrying voltage Vout1 to Vout3 is single voltage Vout.Terminal 36A to 36C is connected to the anode-side of series load 32A, with detection Any short trouble in high-side driver circuit 50.

As described above, load voltage Vout depends on series load, rather than the output of current source 14 to 18.Series load All LED voltage drops in 32A are roughly the same in the example of Fig. 3 A, therefore series load voltage Vout is Vout=N x V_LED=3x V_LED, wherein N is the integer for indicating the load number in series load 32A.

Similar to what is described in Figure 1A, the selector circuit of circuit 50A is minimum value selector 20.Minimum value selector 20 Multiple input voltages are received, and select the voltage with minimum voltage value.In the example of circuit 50, there is only a series connection Load voltage Vout, therefore, V_SELECT=Vout.In other examples (all combination examples described above), minimum value selection The function of device 20 can be similar to the function of contacting Figure 1A description.Circuit 50 depicts the short-circuit detecting of the technology according to the disclosure An advantage in the advantages of circuit.As being described more fully, identical multichannel short-circuit detecting circuit can be with It is used together with multiple series loads or single series load with any combination.

The comparison circuit (comparator 22) of circuit 50A receives Vselect 38 in anti-phase input, and by Vselect 38 are compared with predetermined threshold voltage Vthresh 24.Meet in response to selected series load voltage Vselect 38 pre- Determine threshold voltage value Vthresh 24, circuit 50A is configurable to export in short-circuit detecting and export at (output of comparator 22) Short-circuit detection signal Vflag 28.

Other numbers or analog circuit 26 can receive short-circuit detection signal Vflag 28 from the output of circuit 50A, and And other functions are executed using Vflag.As described above, other functions may include: to send alert message or starting warning Indicator (such as indicator light), the warning indicator is by there may be short circuit notices to give in a LED in the LED of series LED User.

Fig. 3 B is to depict to drive the more of single led series load according to the having for one or more kinds of technologies of the disclosure Channel high side connects the conceptual timing diagram of the operation of the short-circuit detecting circuit of drive circuit.The timing chart sketches of Fig. 3 B Fig. 3 A LED 25 have short trouble example in operation.

The timing diagram of Fig. 3 B includes the curve graph of the curve graph of Vout, the curve graph of Vselect 38 and Vflag 28. LED 25 forms short circuit into t1 in period t0, it means that V_LED25In period t0 to essentially a zero during t1.Vout is series connection The series load voltage of 32A is loaded, and in the example of Fig. 3 B, the substantially identical value V of all LED voltage drops_LED.Therefore, In period t0 to during t1, Vout will be from about 3V_LEDIt is decreased to about 2V_LED.Therefore, at substantially t0, Vselect will also subtract As low as about 2V_LED。

Can with Vthresh 24 is selected above with respect to same way described in Figure 1B, this is the skill according to the disclosure Another advantage of the short-circuit detecting circuit of art.Vthresh 24 is selected to depend on the LED in one or more LED series load Known V_LEDi.When compared with the other examples with short-circuit detecting circuit, this simplifies the selections to Vthresh 24.

As in the above-mentioned example with the multiple series loads of multi-path driver circuit drives, short-circuit detecting circuit can To be configured to for selected series load voltage Vselect 38 and predetermined threshold voltage value Vthresh 24 being compared.It rings Predetermined threshold voltage value Vthresh 24 should be met in Vselect 38, short-circuit detecting circuit is configurable in single short circuit inspection Output short-circuit detects signal Vflag 28 at slowdown monitoring circuit output.In Fig. 3 A (high-side driver electricity with single led series load Road) example in, when Vselect 38 be less than Vthresh 24 (Vselect < Vthresh) when, Vselect 38 meets threshold value Vthresh 24.In some instances, circuit 50A is configurable to: when Vselect 38 is less than or equal to Vthresh 24 When (Vselect≤Vthresh), Vselect 38 meets threshold value.

Substantially at time t0, Vselect 38 meets Vthresh 24, and comparator 22 can be detected with output short-circuit Signal Vflag 28.Substantially at time t1, the short trouble of LED 25 no longer exists, and Vout rises back 3x V_LED。 Vselect 38 also increases to 3x V_LED, and no longer meet threshold value Vthresh 24.In response, comparator 22 can when Between stop output short-circuit at t1 and detect signal Vflag 28.

Fig. 4 A is the schematic diagram for illustrating the example low side driver multi-channel circuit of single series load of driving LED. Function by Fig. 4 A circuit 60 described is similar to the circuit 40 of Fig. 2A.Appended drawing reference instruction identical with other figures of the disclosure Component with identical function and performance.

Circuit 60 may include current source 14 to 18, for one or more output element being shorted together (34A to each of 34C) output element transmits or puts into output electric current, to drive one that is coupled to each output element Series load 32A.Circuit 60 including 14 to 18 the two of circuit 60A and current source can be considered short-circuit detecting circuit.At it In its example, circuit 60A can be considered short-circuit detecting circuit, and separate with current source circuit, but extremely via terminal 36A 36C is connected to current source output 34A to 34C.

Described in the Figure 1A as described above of Vbat 12 like that.Vbat 12 is connected to the anode-side of series load 32A.Current source 14 to 18 are connected to the series load 32A including LED 25A.Current source 14 to 18 puts into ource electric current to ground.For simplification figure, Other LED in series load 32A are not numbered.Series load 32A is portrayed as including three LED by the example of Fig. 4 A, But in other examples, series load may include any amount of LED.

Circuit 60A can be considered the short-circuit detecting circuit of circuit 60.Circuit 60A includes selector circuit (maximum value choosing Select device 30), comparison circuit (comparator 22), threshold voltage vt hresh 24A and output Vflag 28.Circuit 60A can be through Series load 32A is coupled to by terminal 36A to 36C, and receives load voltage Vout1 to Vout3, in the example of Fig. 4 A, Load voltage Vout1 to Vout3 is single voltage Vout.Terminal 36A to 36C is connected to the anode-side of series load 32A, with inspection Survey the short trouble in low driver circuit 60.

As Fig. 2 B, load voltage Vout depends on series load, rather than the output of current source 14 to 18.Series connection is negative All LED voltage drops carried in 32A are roughly the same in the example of Fig. 4 A, therefore series load voltage Vout is Vout= Vbat-N x V_LED=Vbat-3x V_LED, wherein N is the integer for indicating the load number in series load 32A.

Similar to what is described in Fig. 2A, the selector circuit of circuit 60A may include maximum-value selector 30.Maximum value choosing It selects device 30 and receives multiple input voltages, and select the voltage with maximum voltage value.In the example of circuit 60, there is only one A series load voltage Vout, therefore, V_SELECT=Vout.It is maximum in other examples (all combination examples described above) The function of value selector 30 can be similar to the function of contacting Fig. 2A description.Circuit 60 is depicted according to the short of the technology of the disclosure An advantage in the advantages of alignment detection circuit.Using high-side driver or low driver circuit, identical multichannel is short Alignment detection circuit can be used together with multiple series loads or single series load with any combination.

The comparison circuit (comparator 22) of circuit 60A receives Vselect 38 in non-inverting input, and will Vselect 38 and predetermined threshold voltage Vbat 12-V_THRESH24A is compared.In response to selected series load voltage Vselect 38 meets predetermined threshold voltage value Vbat 12-V_THRESH24A, circuit 60A are configurable to export in short-circuit detecting Output short-circuit detects signal Vflag 28 at (output of comparator 22).

Other numbers or analog circuit 26 can receive short-circuit detection signal Vflag 28 from the output of circuit 60A, and And other functions are executed using Vflag.As described above, other functions may include: to send alert message or starting warning Indicator (such as indicator light), the warning indicator is by there may be short circuit notices to give in a LED in the LED of series LED User.

Fig. 4 B is depicted according to one or more kinds of technologies of the disclosure for powering to a LED series load Multichannel downside connects the conceptual timing diagram of the operation of the short-circuit detecting circuit of drive circuit.The timing chart sketches of Fig. 4 B figure The operation in the example that LED 25A has short trouble of 4A.

The timing diagram of Fig. 4 B includes the curve graph of the curve graph of Vout, the curve graph of Vselect 38 and Vflag 28. LED 25 forms short circuit into t1 in period t0, it means that V_LED25In period t0 to essentially a zero during t1.Vout is series connection The series load voltage of 32A is loaded, and in the example of Fig. 4 B, the substantially identical value V of all LED voltage drops_LED.Therefore, In period t0 to during t1, Vout will be from about Vbat-3V_LEDIncrease to about Vbat-2V_LED。

It is configured to receive series load electricity from each of one or more output element output element 34A to 34C The selector circuit for pressing Vout1 to Vout3 is maximum-value selector 30.Maximum-value selector 30 is configurable to selection from one The maximum series load voltage of a or multiple output elements.In the example of circuit 60, there is only a series load voltages Vout, therefore, V_SELECT=Vout.In other examples (all combination examples described above), the function of maximum-value selector 30 Energy can be similar to the function of contacting Fig. 2A description.At time t0, maximum-value selector 30 exports Vout as Vselect 38.Therefore, substantially at t0, Vselect also will be about Vbat-2V_LED。

Can with Vthresh 24 is selected above with respect to same way described in Fig. 2 B, this is the skill according to the disclosure Another advantage of the short-circuit detecting circuit of art.As above in the example of the multiple series loads of multi-path driver circuit drives Like that, short-circuit detecting circuit is configurable to selected series load voltage Vselect 38 and predetermined threshold voltage value Vbat 12-Vthresh 24A is compared.Meet predetermined threshold voltage value Vbat 12-Vthresh in response to Vselect 38 24A, short-circuit detecting circuit are configurable to the output short-circuit at single short-circuit detecting circuit output and detect signal Vflag 28.

In the example (it is low driver circuit) of Fig. 4 A, when Vselect 38 is greater than Vbat 12-Vthresh When 24A (Vselect > Vbat-Vthresh), Vselect 38 meets threshold value Vbat 12-Vthresh 24A.In some examples In, circuit 60A is configurable to: when Vselect 38 is more than or equal to Vthresh 24A (Vselect >=Vbat- When Vthresh), Vselect 38 meets threshold value.

Substantially at time t0, Vselect 38 meets Vbat 12-Vthresh 24A, and comparator 22 can export Short-circuit detection signal Vflag 28.Substantially at time t1, the short trouble of LED 25 no longer exists, and Vout is decreased to Vbat–3V_LED, so that Vselect38 be made also to be decreased to Vbat-3V_LED.At time t1, Vselect 38 no longer meets threshold value Vbat12-Vthresh 24A.In response, comparator 22 can stop output short-circuit detection signal Vflag at time t1 28。

Fig. 5 is shown according to the concept of the example embodiment of the short-circuit detecting circuit of one or more kinds of technologies of the disclosure Meaning property block diagram.The function of circuit 70 can be similar to circuit 10A and 50A, and circuit 70 can connect drive with triple channel high side Dynamic device circuit is used together.This is only a kind of example embodiment according to the short-circuit detecting circuit of the technology of the disclosure.It is other Example may include different component and component configuration.

Similar to foregoing circuit 10A and 50A, short-circuit detecting circuit 70 includes comparator 22 and selection circuit (minimum value choosing Select device 20).Terminal OUT1 to OUT3 provides input to minimum value selector 20.Terminal OUT1 to OUT3 can be with Figure 1A to figure Terminal 36A to the 36C association described in 4A.Terminal OUT1 to OUT3 can connect to three individual series load (such as Figure 1A It is discribed with Fig. 2A), be connected to any group of single series load (such as Fig. 3 A and Fig. 4 A are discribed) or series load It closes.The other examples of circuit 70 may include more than three terminals described in Fig. 5 or less terminal.

The output of minimum value selector 20 is connected to the anti-phase input of comparator 22 by resistor 42.Comparator 22 it is anti- Mutually input is connected to the ground by resistor 48.Resistor 42 and resistor 48 form the partial pressure of the anti-phase input for comparator 22 Device.

The associated threshold voltage of Vthresh 24 that the non-inverting input of comparator 22 receives and Figure 1A describes into 4A is set It sets.Electric current Iref is supplied to resistor Rref 54 by reference to voltage pin 56 by current source 52.It may need Zener diode 50 to provide protection in the case where overvoltage.In some instances, the clamp voltage provided by Zener diode 50 can be with Limit the maximum quantity of the LED in LED chain.User can select threshold voltage by selecting the value of external resistor Rref54 Value.As described above, threshold voltage can be selected as it is V smaller than the expection series load of global function series load_LEDSome portion Point.V_LEDPart can be 1/2V_LED、1/3V_LED、1/4V_LEDOr V_LEDSome other parts, ensure short-circuit detecting electricity Road will test the single short circuit load in series load, while avoid false detection instruction.External reference voltage pin 56 Provide a user the option for carrying out adjusting threshold voltage based on application, wherein the SLS in Fig. 5 refers to single led short-circuit (SLS) ginseng It examines.

The output of comparator 22 can connect the mistake manages circuit 32 into the example of Fig. 5.Mistake manages circuit 32 connects It is connected to control circuit 34.Mistake manages circuit 32 and control circuit 34 can be with other numbers for describing in Figure 1A to Fig. 4 A above Word or analog circuit 26 are associated with.The example of circuit 70 does not have for detecting the single led short circuit event in LED chain or string External, the additional or dedicated pin of barrier.

In operation, circuit 70 is configurable to the selected series load voltage that will be exported from minimum value selector 20 It is compared with the predetermined threshold voltage value being arranged by resistor Rref 54 as described above.In response to such as by by resistor The selected series load voltage of the 42 and 48 divider scalings formed meets predetermined threshold voltage value Vthresh 24, short circuit Detection circuit 70 is configurable to output short-circuit detection signal similar with the Vflag 28 described in Figure 1A to Fig. 4 A.In Fig. 5 Example (it will work together with high-side driver circuit) in, minimum value selector 20 selects minimum series load voltage.Such as Above in connection with Figure 1A and Fig. 3 A description, when selected voltage is less than or is less than or equal to predetermined threshold voltage (such as Vselect < Vthresh) when, selected voltage meets threshold value.In some instances, such as in Figure 1A to Fig. 4 A, series connection Scale factor between load voltage and the input of comparison circuit (such as comparator 22) is the scale factor for 1.Figure 1A extremely schemes The other examples of 4A can also include scaling circuit similar with the scaling circuit described in Fig. 5.

The single short-circuit detection signal exported from comparator 22, which may be enough to mark, is connected to appointing for terminal out1 to out3 Short-circuit LED or other loads in what series load.As described above, this, which can be provided, does not need additional pins or complexity To detect the advantage of the single short circuit in multiple LED series loads.Mistake manages circuit 32 and control circuit 34 can respond Other functions are executed in receiving short-circuit detection signal.These functions may include: to send alert message or starting warning Indicator, closing have the function of the series load of short-circuit LED, the spare LED chain or other similar of starting.

Fig. 6 is in a load in a series of loads of detection illustrated according to one or more kinds of technologies of the disclosure Short circuit circuit device operation example modes flow chart.The step of Fig. 6 will be described mainly according to Figure 1A, Figure 1B and Fig. 3 A Suddenly, but the step of Fig. 6, can be applied to other examples.

As described above, the circuit 10 and 50 described respectively in Figure 1A and Fig. 3 A may include current source 14 to 18, to be used for To circuit one or more output element (34A to each of 34C) output element transmission go to be coupled to it is each defeated Series load (output electric current (the Iout1 to Iout3) (90) of 32A to 32C) of element out.Circuit 10 can be considered short-circuit inspection Slowdown monitoring circuit, and including current source 14 to 18.In other examples, short-circuit detecting circuit can only include circuit 10A or 50A, circuit 10A or 50A can be separated with current source circuit, but be connected to current source output 34A via terminal 36A to 36C To 34C.In other words, in other examples, short-circuit detecting circuit may include source (such as electric current for powering to series load Source).In other examples, in the example for the circuit 70 such as described in Fig. 5, short-circuit detecting circuit can not have for string Join the source of load supplying.

Each series load 32A to 32C may include N number of load, such as N number of LED.Series load 32A to 32C is depicted The series load of N=3, but in other examples, N may be greater than 1 any integer.Short-circuit detecting circuit can determine coupling To one or more output element one or more series load (corresponding series load of the 32A into 32C) it is corresponding Series load voltage (Vout1 to Vout3) (92).Series load voltage depends on the electricity at each load both ends in N number of load The value of pressure drop and the quantity (N) of load.In the example of fig. 1, series load 32B includes three LED (N=3), and every A LED voltage drop can be 0.7V.Therefore, the series load voltage of corresponding series load 32B is 3x 0.7V=2.1V.At it In its example, corresponding series load may include the different types of LED of one or more that there are different voltages to drop.Corresponding string Connection load voltage by be each LED in series load or other types of load voltage drop summation.

Short-circuit detecting circuit may include selector, such as minimum value selector 20 or maximum-value selector 30.Scheming In the example of 1A, minimum value selector 20 be can choose with the minimum series load in one or more series load voltage The series load of voltage (as selected series load voltage).In the example of Figure 1A because LED 25 may have it is short Road failure (such as time t in fig. ib₀Place), so Vout1 can be less than Vout2 or Vout3.In other words, in time t₀ With time t₁Between, Vout1 is the minimum series load voltage in one or more load voltage.Minimum value selector 20 from Select the Vout1 of series load 32A as selected series load voltage in one or more series load voltage (Vselect 38)(94).In the other examples such as above in connection with Fig. 2A and Fig. 4 A description, maximum-value selector 30 can be with Select maximum load voltage as selected series load voltage from one or more series load voltage.

The circuit 10A of circuit 10 may include comparator 22, which can be by selected series load voltage (Vselect 38) is compared with threshold voltage vt hresh 24.Comparator 22 can determine selected output voltage (Vselect=Vout1) whether meet predetermined threshold voltage value (Vthresh) (96).In the example of Figure 1A, in Figure 1B In time t₀With t₁Between describe, when Vselect 38 is less than Vthresh (Vselect < Vthresh), Vselect 38 is full Sufficient predetermined threshold Vthresh 24.In some instances, when Vselect 38 is less than or equal to 24 (Vselect of Vthresh ≤ Vthresh) when, comparator 22 is configurable to output short-circuit detection signal Vflag (28).In other examples (such as Fig. 2A Example) in, when Vselect 38 be greater than Vthresh (Vselect > Vthresh) when, Vselect 38 meets predetermined threshold Vthresh。

Meet threshold voltage value (Vthresh) in response to the selected output voltage of determination (Vselect=Vout1), it is all Such as the time t described in fig. ib₀The comparator 22 at place, short-circuit detecting circuit can detect signal Vflag 28 with output short-circuit, (98).Other numbers or analog circuit 26 can receive short-circuit detection signal Vflag (28), and be executed using Vflag Other functions.In some instances, other functions may include: and send alert message or start warning indicator (such as to refer to Show lamp), which will have short circuit notice to user in a LED in the LED in series LED.

Example 1: a kind of circuit including short-circuit detecting circuit, the short-circuit detecting circuit include: single short-circuit detecting output Element；And selector circuit, the selector circuit are configured to export member from each of one or more output element Part receives series load voltage, and selects a series load voltage from one or more output element, wherein should Short-circuit detecting circuit, which is configured that, is compared selected series load voltage with predetermined threshold voltage value, and in response to Selected series load voltage meets predetermined threshold voltage value, and short-circuit detecting circuit is configured to defeated in single short-circuit detecting circuit Source output short-circuit detects signal.

Example 2: the circuit of example 1, wherein short-circuit detecting circuit is configured to the output short-circuit detection letter during startup stage Number, and short-circuit detecting circuit is configured to the output short-circuit during the operation phase and detects signal.

Example 3: the circuit of any one of example 1 to 2 or any combination thereof, the circuit further include that one or more is defeated Element out, wherein each output element, which is configured to that electric current will be exported, is sent to the series load including N number of load, wherein N is Integer greater than 1.

Example 4: any combination of circuit of example 1 to 3, wherein threshold voltage value is inputted in response to user and be can adjust.

Example 5: any combination of circuit of example 1 to 4, wherein selector circuit is minimum value selector circuit, this is most Small value selector circuit configuration be determine one or more output element at one or more output voltage in most Small voltage, and the minimum voltage is selected as selected output voltage.

Example 6: any combination of circuit of example 1 to 5, wherein selector circuit is maximum-value selector circuit, this is most Big value selector circuit configuration be in one or more output voltage at one or more output element of determination most Big voltage, and the maximum voltage is selected as selected output voltage.

Example 7: any combination of circuit of example 1 to 6, wherein short-circuit detection signal is configured to be explained by external circuit There is the instruction of short circuit fault at least one of N number of load load.

A kind of example 8: system comprising: multiple LED strings, in which: each LED string in multiple LED strings includes N number of string The LED of connection, wherein N is greater than 1 integer, and each LED in N number of LED in LED string has expected forward drop； Drive circuit, the drive circuit include multiple output elements, in which: and each corresponding output element is coupled to corresponding LED string, And drive circuit is configured to for the corresponding output electric current from each corresponding output element to be sent to each corresponding LED string； Selector circuit, the selector circuit are configured to select the series load voltage in multiple series load voltages, wherein multiple strings Join the corresponding series load voltage of each of load voltage to correspond to the corresponding LED string in multiple LED string；Comparison circuit, the ratio Compared with circuit configuration are as follows: determine whether selected series load voltage meets predetermined threshold voltage value, and in response to determining institute The series load voltage of selection meets predetermined threshold voltage value, and output short-circuit detects signal.

Example 9: the system of example 8, wherein threshold voltage value is provided so that as any LED in multiple LED string When single short-circuit state occurs in any LED in N number of LED in string, comparison circuit output short-circuit detects signal.

Example 10: any combination of system of example 8 to 9, wherein selector circuit is minimum value selector circuit, should Minimum value selector circuit configuration is minimum series load voltage to be determined from multiple series load voltages, and the minimum is gone here and there Connection load voltage is selected as selected output voltage；Each output element of drive circuit is configured to from each corresponding LED Corresponding output electric current is sent to corresponding LED and gone here and there by the high side of string.

Example 11: any combination of system of example 8 to 10, wherein selector circuit is maximum-value selector circuit, should Maximum-value selector circuit configuration is maximum series load voltage to be determined from multiple series load voltages, and the maximum is gone here and there Connection load voltage is selected as selected output voltage；Each output element of drive circuit is configured to from each corresponding LED Corresponding output electric current is sent to corresponding LED and gone here and there by the downside of string.

A kind of example 12: method comprising: by short-circuit detecting circuit and to one of the short-circuit detecting circuit or The output for each series load for being coupled to each output element is gone in each of multiple output elements output element, transmission Electric current, in which: each series load includes N number of load, and N is greater than 1 integer；Coupling is determined by short-circuit detecting circuit It is bonded to the corresponding series load of the corresponding series load in one or more series load of one or more output element Voltage；Selected series load voltage is selected from one or more series load voltage by short-circuit detecting circuit；It is logical It crosses short-circuit detecting circuit and determines whether selected output voltage meets predetermined threshold voltage value；And in response to selected by determination Output voltage meet threshold voltage value, pass through short-circuit detecting circuit output short-circuit detect signal.

Example 13: the method for example 12, wherein when short-circuit detecting circuit is in operation mode, short-circuit detecting circuit is matched It is set to and each of one or more output element output element is sent to for electric current is exported with predetermined duty ratio, wherein Operation mode includes startup stage and operation phase, and short-circuit detecting circuit is configured to determine in any stage of operation mode Whether the first output voltage meets threshold voltage value.

Example 14: any combination of method of example 12 to 13, wherein selector circuit is minimum value selector circuit, The minimum value selector circuit configuration are as follows: determined from one or more output voltage from one or more output element Minimum voltage；And the minimum voltage is selected as selected output voltage.

Example 15: any combination of method of example 12 to 14, wherein each output element of short-circuit detecting circuit configures To be coupled to the corresponding series load of each of each corresponding output element from the driving of the high side of each corresponding series load.

Example 16: any combination of method of example 12 to 15, wherein selector circuit is maximum-value selector circuit, The maximum-value selector circuit configuration are as follows: determined from one or more output voltage from one or more output element Maximum voltage；And the maximum voltage is selected as selected output voltage.

Example 17: any combination of method of example 12 to 16, wherein each output element of short-circuit detecting circuit configures To be coupled to the corresponding series load of each of each corresponding output element from the low side drive of each corresponding series load.

Example 18: any combination of method of example 12 to 17, wherein each of each series load of N number of load Load is light emitting diode (LED), and each LED in LED has expected forward drop, and wherein, threshold voltage value quilt It is chosen so as to threshold voltage value and is equal to the approximately half of of expected forward voltage.

Example 19: any combination of method of example 12 to 18, wherein threshold voltage value is adjustable in response to user's input It is whole.

Example 20: any combination of method of example 12 to 19, wherein threshold voltage value, which is provided so as to work as, to be coupled In any load in N number of load in any series load in the series load of any output element into output element When single short-circuit state occurs, short-circuit detecting circuit output short-circuit detects signal.

The various examples of the disclosure have been described.These and other example is within the scope of the appended claims.

Claims

1. a kind of circuit including short-circuit detecting circuit, the short-circuit detecting circuit include:

Single short-circuit detecting output element；And

Selector circuit, the selector circuit are configured as each output element from one or more output element and connect Series load voltage is received, and selects a series load voltage from one or more of output elements,

Wherein, the short-circuit detecting circuit is configured as:

Selected series load voltage is compared with predetermined threshold voltage value, and

Meet the predetermined threshold voltage value in response to selected series load voltage, the short-circuit detecting circuit is configured as Output short-circuit detects signal at the single short-circuit detecting circuit output.

2. circuit according to claim 1, wherein the short-circuit detecting circuit is configured as exporting during startup stage The short-circuit detection signal, and the short-circuit detecting circuit is configured as exporting the short-circuit detecting letter during the operation phase Number.

3. circuit according to claim 1 further includes one or more output element, wherein each output element quilt Electric current will be exported by, which being configured to, is sent to the series load including N number of load, wherein N is greater than 1 integer.

4. circuit according to claim 1, wherein the threshold voltage value is inputted in response to user and be can adjust.

5. circuit according to claim 1, wherein the selector circuit is minimum value selector circuit, the minimum Value selector circuit is configured as determining from one or more output voltage from one or more of output elements Minimum voltage, and select the minimum voltage as selected output voltage.

6. circuit according to claim 1, wherein the selector circuit is maximum-value selector circuit, the maximum Value selector circuit is configured as determining from one or more output voltage from one or more of output elements Maximum voltage, and select the maximum voltage as selected output voltage.

7. circuit according to claim 1, wherein the short-circuit detection signal is configured as being construed to N by external circuit At least one of a load load has the instruction of short circuit fault.

8. a kind of system, comprising:

Multiple LED strings, in which:

Each LED string in the multiple LED string includes concatenated N number of LED, wherein and N is greater than 1 integer, and

Each LED in N number of LED in LED string has expected forward drop；

Drive circuit, the drive circuit include multiple output elements, in which:

Each corresponding output element is coupled to corresponding LED string, and

The drive circuit is configured as the corresponding output electric current from each corresponding output element being sent to each corresponding LED string；

Selector circuit, the selector circuit are configured as selecting the series load voltage in multiple series load voltages, In, the corresponding series load voltage of each of the multiple series load voltage and the multiple LED go here and there in corresponding LED string pair It answers；

Comparison circuit, the comparison circuit are configured as:

Determine whether selected series load voltage meets predetermined threshold voltage value, and

Meet the predetermined threshold voltage value in response to the selected series load voltage of determination, output short-circuit detects signal.

9. system according to claim 8, wherein the threshold voltage value is provided so that: when in the multiple LED When single short-circuit state occurs in any LED in N number of LED in any LED string in string, the comparison circuit output The short-circuit detection signal.

10. system according to claim 8, in which:

The selector circuit is minimum value selector circuit, and the minimum value selector circuit is configured as from the multiple string Join and determine minimum series load voltage in load voltage, and selects the minimum series load voltage as selected output Voltage；

Each output element of the drive circuit is configured as accordingly exporting electric current biography from the high side that each corresponding LED goes here and there It send to corresponding LED and goes here and there.

11. system according to claim 8, in which:

The selector circuit is maximum-value selector circuit, and the maximum-value selector circuit is configured as from the multiple string Join and determine maximum series load voltage in load voltage, and selects the maximum series load voltage as selected output Voltage；

Each output element of the drive circuit is configured as accordingly exporting electric current biography from the downside that each corresponding LED goes here and there It send to corresponding LED and goes here and there.

12. a kind of method, comprising:

Pass through short-circuit detecting circuit and each output into one or more output element of the short-circuit detecting circuit The output electric current for each series load for being coupled to each output element is gone in element, transmission, in which:

Each series load includes N number of load, and

N is greater than 1 integer；

It is determined by the short-circuit detecting circuit and is coupled to the one or more of one or more of output elements The corresponding series load voltage of corresponding series load in a series load；

Selected series load is selected from one or more of series load voltages by the short-circuit detecting circuit Voltage；

Determine whether selected output voltage meets predetermined threshold voltage value by the short-circuit detecting circuit；And

Meet the threshold voltage value in response to the selected output voltage of determination, passes through the short-circuit detecting circuit output short-circuit Detect signal.

13. according to the method for claim 12, in which:

When the short-circuit detecting circuit is in operation mode, the short-circuit detecting circuit is configured as institute with predetermined duty ratio State each output element that output electric current is sent in one or more of output elements, wherein the operation mode packet Startup stage and operation phase are included, and

The short-circuit detecting circuit is configured as determining whether the first output voltage meets in any stage of the operation mode Threshold voltage value.

14. according to the method for claim 12, wherein the selector circuit is minimum value selector circuit, it is described most Small value selector circuit is configured as:

Minimum voltage is determined from one or more output voltage from one or more of output elements；And

Select the minimum voltage as selected output voltage.

15. according to the method for claim 14, wherein each output element of the short-circuit detecting circuit be configured as from The high side driving of each corresponding series load is coupled to the corresponding series load of each of each corresponding output element.

16. according to the method for claim 12, wherein the selector circuit is maximum-value selector circuit, it is described most Big value selector circuit is configured as:

Maximum voltage is determined from one or more output voltage from one or more of output elements；And

Select the maximum voltage as selected output voltage.

17. according to the method for claim 16, wherein each output element of the short-circuit detecting circuit be configured as from The low side drive of each corresponding series load is coupled to the corresponding series load of each of each corresponding output element.

18. according to the method for claim 12, wherein each load of each series load of N number of load is luminous two Pole pipe (LED), each LED in the LED have expected forward drop, and wherein, the threshold voltage value is selected To make the threshold voltage value be equal to the approximately half of of the expected forward voltage.

19. according to the method for claim 12, wherein the threshold voltage value is inputted in response to user and be can adjust.

20. according to the method for claim 12, wherein the threshold voltage value is provided so that: when being coupled to State appointing in N number of load in any series load in the series load of any output element in output element When single short-circuit state occurs in what load, the short-circuit detecting circuit exports the short-circuit detection signal.